1. Field of Invention
The present invention relates to body electrodes, and more particularly to a disposable electrode for use with electro-medical equipment for surgery, therapy and diagnosis such as electrosurgical units, electrocardiographs, monitoring apparatus and ultrasound units.
2. Description of the Prior Act
The electrosurgical unit return electrode provides half of the circuit between the electrosurgical unit and patient. The current must be distributed over a sufficiently large area at the return electrodes to eliminate heating effects.
This reduction of current density (milliamperes) is provided by adequately sized electrodes and by good electrical contact between the return electrode and the patient. The return electrode should reduce the current density so that tissue burns do not occur at the electrode site.
Metal plate-type electrodes have traditionally been used as return body electrodes. Conventional reusable stainless steel return electrodes are not without problems due to design limitations and frequent handling, cleaning and reuse. Some problems are: return cable breakage, return electrode damage (distortion, bending, etc.), difficulty in placement on patient, tissue damage due to damaged plates, storage difficulty, and the unpleasant sensation caused by contact with a metallic plate.
Disposable return electrodes eliminate some of these problems. There are two types of disposable return body electrodes, namely, plate-type and adhesive-type. The present invention relates to an electrode of the latter type.
Because disposable return electrodes are used only once, the probability of physical damage is minimized. No cleaning, sterilization or restorage is required. Some problems of electrode placement (on the body), such as tissue necrosis and excessive heating are eliminated.
Adhesive-backed return electrodes should be capable of remaining securely attached for at least eight hours. Moreover, they typically require minimum skin preparation, and facilitate intentional removal following the operation.
The adhesive should be strong enough to prevent electrode movement while resisting stresses from the electrical return cable applied at its connection to the electrode.
The occurrence of a relatively small contact area between the patient and the conducting element, which can arise when the electrode does not tightly and intimately conform to the adjacent portion of the body, may cause the flow of current to produce undesirable heating or burning. Electrical conducting wetting agents such as electrosurgical gels have been developed to improve the electrical coupling of the return electrode to the patient. They are intended to reduce electrical resistance of the skin and, by virtue of their own electrical conductivity, to improve electrical contact by filling in any air gaps between the return electrode surface and the patient.